Opening theme song link
I had a lot of time on my hands today and found a site which has the theme songs and opening credits (poor quality video though) to Three's a Crowd. I wasn't a fan of this show because Three's a Crowd wasn't as good as its predecessor, Three's Company. However, its opening song was better the original show's.
Copy and paste this link to your address bar to listen to the full one minute opening theme of Three's a Crowd.
http://www.sitcomsonline.com/sounds/threesacrowd.mp3 (great quality audio)
If you want to see the opening credits and read other info on the show, go to this site:
http://www.sitcomsonline.com/threesacrowd.html